As of today (November 22nd 2010), NASA's http://planetquest.jpl.nasa.gov/ page counter shows 500 known / confirmed exoplanets.
Who knows how reliable that counter is, but I think it is something worth mentioning.
18 years since first exoplanet has been discovered and we know of 500 of them. That's 27-28 planets (on average) each year ... which is amazing.
Now waiting for next Kepler announcements.
It should be noted that it's difficult to really say 500 planets have been found. Some of the objects contributing to that number are in the hazy area where we aren't sure what separates a planet from a brown dwarf. Furthermore, there are a number of unconfirmed extrasolar planets which may or may not exist.
But that aside, it is quite uplifting to see 500+ on such counters.
Jean Schneider posted a "warning" about the 500th detection.
http://tamise.ujf-grenoble.fr/wws/arc/exoplanets/2010-10/msg00001.html
That being said, his website (which is usually taken as THE exoplanet counter) now has 504 tallied.
There is also http://www.space.com/scienceastronomy/500th-alien-planet-discovered-101122.html article on space.com.
"[...] The milestone [500 exoplanets] was reached Friday (Nov. 19), according to the Extrasolar Planets Encyclopedia, a database compiled by astrobiologist Jean Schneider of the Paris-Meudon Observatory."
Can bump that number up by 5-7 today with a big haul from the HARPS search. Up to 6 planets (5 for sure) within 1.5AU, all Neptune-sized and one possible Super-Earth! Then the 7th out at 3.5AU being a little smaller than Saturn. That's one jam-packed system!
http://arxiv.org/abs/1011.4994
These jammed low-mass systems sound like very interesting places. I do wonder if moons are fairly rare in them, though. Seems as if all but the closest satellites to their primaries would be (relatively) quickly stripped away via interactions with the other planets in such close proximity.
The planets at HD 10180 have been known for a while now. They were made public in an http://www.eso.org/public/news/eso1035/ last August. As typically happens for these press releases, the paper appears on arXiv some time after.
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