I'm not sure if anyone outside of the site founders knows exactly the formula for the recommended diary list. One thing I suspect though is that each individual has their own "rules and values" for recommending diaries. I list mine below and would enjoy reading yours in the comments.
As an aside I would like to mention that the diaries on the Recommended List are the first articles on any given day I read as soon as my computer boots, and the coffee pot drips, in the morning. Before the front page even, nowadays. Therefore how those scant 8 of many many well written diaries reach that point is of some interest to me, and how the community gets them there, based on each person's own values and quirks.
1) I ALWAYS read the whole diary before recommending. Even Hunter's. Corollary: I NEVER recommend without reading the whole diary first.
2) I never "auto-rec" just because of the author. I've recommended every OrangeCloud and RighteousBabe diary I've ever read. But I've always read them first.
3) I NEVER "auto-rec" for our elected friends posting here (Kerry, Barb, etc). This is certainly not to say I don't enjoy their contributions to the community immensely, and will gladly recommend once I've read the diary. My sensibility is I'll give the same weight to what they say and how well they say it as I would to someone I don't know at all. My perosnal value is I feel that's appropriate to this particular community, where the "nobody person" would have no say on the US House or Senate floor.
Also, I figure enough people out there "auto-rec" a Kerry diary so it'll always be #1 in 2 seconds no matter what.
4) It's not a general rule, but I relax my standards for diaries which are not currently on the rec list.
5) What kind of mood I'm in will definitely effect my recommendation criteria, adding a bit of randomness to the process. For example if I was just over at foxnews.com and I come back to DKOS to a snark diary, the dark cloud may not lift enough to get the recommend over a particularly angry and unjust diary.
In fact this is the most important rule, or factor I should say since some days I recommend everything I read and others I forget the button is even there. This is sort of the "yeah, whatever...." rule.
6) As far as a whole bunch of stuff I've seen people swing violently one way or the other on "never recommend this or that," like the BREAKING title line, I instead read the diary before deciding to rec, title be damned. A catchier title will definitely increase the probability of me reading your diary though.
7) I always recommend bonddad's diaries. I know this contradicts rule #2, but us liberals are all hypocrits and liars anyways. So it's all good :)
8) KOS has never left a comment to one of my comments or diaries and I feel very hurt inside. I have to cry myself to sleep. But as a revenge tactic I pronouce it dailyKOS, as in "cause" and not dailyKOS as in "coze," when talking about the community with my friends. HA!
I WANNA HEAR YOUR 'RULES' AND OTHER STUFF!!!