More than a year old? Any new sites (0 to 4 months old) are not really stable in the SERP unless Google has counted already many quality links.
I've had this same problem too for some weeks now. I purchased a bunch of highly targeted strong links including sitewides and the 3 or 4 keywords i was ranking highly on have disapeared. I purchased those links in quite a short time range. I was told the same over promotion of the same keyword but i have done nothing but use different words and am having the same problem. I don't know how long it will go on for but its quite disheartening and sucks.
Can be Sandbox or filtered out. Check other keywords. There's no easy explanation for that. I have over 3-year domain, listed in DMOZ, used to be in top 3 on main keyword for last 3 years. Month ago it was filtered out on main keyword. Can you believe it? 3-year, DMOZ listed, unique web site - was OK for 3 years, but not now. This is good developer site, unique content, the only so unique and so close to the keyword among all competitors. I can see 5/10 trash web sites in TO10, but not my 3-year-old web site. This shows it can happen to any site, for any reason... And we cannot do anything with that. Just Google - this is machine - brain-less machine... sizzler_chetan If you have Google sitemap - remove it from your account - sometimes helps. Also check in Webmaster account for 404 header pages.
Dargre.. I dont have sitemap in webmaster account yet. And never thought of any other kind of tricks of SEO rather than backlinks.. As others said, i would just have to wait and see what happens.
Chetan i told you i had a similar problem with one of my directory prior to the update, all the terms it was ranking for previously were lost and it was for a good 10-15 days than it was stable for a week and again went down for a 10 days, and after that the PR updated and i got PR 5, it was all normal for a week and there were ups and downs 2-3 times for a few intervals and since than its back and normal and rock and steady. I am sure you have the same problem! You might get a good surprise this update though~
This thread has just made me write 4 new Titles immediately for a directory im currently submitting. I have no idea whats up but as many are saying not to worry i will advise that too, i understand Quantum Physics easier than i do search engines at times, lol Hope things get back to normal for you soon, probably better infact.
Hope for that.. for the best! Was a big change.. so had to worry. Yep this would be my next step, contacting him yep hoping something good in future atleast!
Same thing happened here today. I target for keywords similar to yours also. hah. My directory is around 16 months old and it has never been dropped before. Not once. Though this happens to many of my other sites so I guess you just gotta wait it out. Maybe I will try changing some of the anchors I use.