Paul Graham ForbesMartin Kleppman, a co-founder of Rapportive, a cool startup that adds social profiles of the people who email you to your Gmail, has a blog post up about Y Combinator, the top Silicon Valley startup accelerator, saying he didn't enjoy it.

Startups spend three months months at Y Combinator working like crazy and getting mentoring and support, and at the end crowds of angels and VCs beat each other up to put money into the companies. What's not to love about that for a startup?

The gist is basically this: when Rapportive entered Y Combinator, they already had a live product. Most startups who join Y Combinator have a demo at most, and so all the startups are focusing together on building their product, which creates more camaraderie and shared insights.

Meanwhile, at that stage Rapportive was all about fixing bugs and responding to user queries, which put them out of step with the other startups, which made the whole experience much less enjoyable for them.

Kleppman does credit Y Combinator with giving great mentorship and being a great program, but warns: if your startup already has a product, Y Combinator is still great, but you're going to enjoy it less. So there you go.

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