Chat programs usually put the most recent information or message below others (bottom posting). Forums and feeds put the most recent information above others (top posting). Is any one better than the other?

It seems like a usecase thing. We read from top-to-bottom, so if you're interested in the latest post or information you'll do a top-down solution. But, if you're interested in the history of a conversation, it is easier to read old messages at the top, like reading a conversation in a book.

But what happens when the these two instances are crossed? What happens when you want to create something that is like a forum but also like a messenger? I see this with twitter. Twitter is a feed system, but also a messaging system when tweets are replies to other tweets. Twitter reverses the order of tweets when looking at a chain of tweets all @replied together, but is this reversing of order good?

Same goes for comment systems. You have comments about something, and you put the most recent at the top. But when you want to reply to a comment, you start a thread and reverse the order, most recent at the bottom. But, what if you're interested in these replies and don't want to just barry them in a thread? Then you'd have to do something similar to YouTube comments, put a link to the previous comment to get the context of the reply.

There has to be a solution better than this? On twitter, if you want context to a tweet, you click on it to view the previous tweets. Same with Youtube, as described above, you click a link button to get context.

So, my question is, can we invent something better than top-posting or bottom-posting; something that is in the middle, but doesn't require much thinking for the user (no no action to take to get context, usually scrolling is better)? Also, something that doesn't reverse order semantics.

  • There are lots of experimental interfaces out there and I think it's somehow easier to envision such a paradigm changing interface within a context: what are we trying to solve, what is important to the audience and last but not least the business constraints. – TotemFlare Apr 8 '13 at 23:37

Trying to find a more complicated solution that feels natural is a recipe for failure. Keep it simple. Even if it isn't 100% perfect for all cases, as long as it's clear, you get most of the benefit.

News feeds should use a top posting as the newest feed is the most important. This can also apply to commenting if the newest comments are more important.

Conversation type applications should use bottom posting as that is the reading flow, and what you need to follow a conversation. I would argue that this should also be used for most comments, as comments are a form of conversation.

Applications that you believe are hybrids that need some combination of the two should be bottom posting. The only disadvantage that this has is that the newest is not at the top. Conversations in it will be clear and coherent, and people can easily learn to look at the bottom or last page for the newest content. Complicating things more by having different parts in different orders will just be confusing and hurt the UX.

  • Like chaiguy mentions, Facebook mixes it up: the news feed is top posting, but the replies on an item are bottom posted. I've always found that to be completely natural. Having to scroll down after each F5 would be a nightmare though. What's your take on that? – Koen Lageveen Apr 9 '13 at 6:29
  • @KoenLageveen that isn't a hybrid. That is news one way and comments another. – JohnGB Apr 9 '13 at 8:18

Consider facebook:

  • The newsfeed is top-down with posting on the top.
  • The chat windows, the posting is bottom-top with posting on the bottom.

Does this irritate you? Did you even notice this?

My opinion (not based on any research that I am aware of), for a top-down reading audience (english language) we have been accustomed to scrolling down to find stuff, to reach end. example: in a document you scroll down to reach the end of a document, in a folder, you scroll down to reach the end of the files, etc.

In a chat messenger, you are not that inclined to dig down in the past and look for artifacts(for the most part), and as the act of archiving messages is list pushing on a stack of items (top or bottom). In a chat window, we can see the most recent past messages and they provide enough context to carry on the conversation, since for the most part long conversations will be almost real time. Again, since we read top down, it made sense to add the history on top and the latest article on the bottom. It is comfortable to read top-down if we want to read history.

In a news feed, the goal of the page is to keep the user engaged for as long as possible (let's face it, it is no noble cause). You can consider your feed as a bottomless pit. You keep on scrolling and scrolling, discovering posts, images, etc. and see no visible ending. Whenever you know there is content below the fold, you are curious to see what is there, here, in the feed, we have an ending below the fold content. And the content is (hopefully) engaging enough to keep the user hooked. Now, if you designed a bottom up newsfeed, you can argue for the same cause, but does it feel natural to you? Endless top scrolling?


One solution (employed by Facebook for example) is to sort top-level posts top-down with the most recent at the top, but to sort replies to a post in bottom-up conversational fashion, so that it's more natural to read the conversation for a particular post.

The reason this works is that most of the time top-level posts are independent of one another, while replies tend to only make sense when read in chronological order.

So as a general "rule of thumb", I would suggest:

  • Use top-down (most recent first) ordering among items that are largely independent, and
  • Use bottom-up (most recent last) ordering among items conversationally dependent on one another

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