Frank Yunker and Stephen Barry, in a study of online courses and how they can be improved through podcasting, have found that these slang terms, and emoticons as well, are "often misunderstood" by students and are "difficult to decipher" unless their meanings are explained in advance. They single out the example of "ROFL" as not obviously being the abbreviation of "rolling on "the" floor laughing" (emphasis added). Matt Haig singles out LOL as one of the three most popular initialisms in Internet slang, alongside BFN ("bye for now") and IMHO ("in my honest/humble opinion"). He describes the various initialisms of Internet slang as convenient, but warns that "as ever more obscure acronyms emerge they can also be rather confusing". Hossein Bidgoli likewise states that these initialisms "save keystrokes for the sender but [...] might make comprehension of the message more difficult for the receiver" and that "lang may hold different meanings and lead to misunderstandings especially in international settings"; he advises that they be used "only when you are sure that the other person knows the meaning".