I had some sites which is on same IP. Before some months my two sites got penalties by Google and all the keywords were down for 1 months. Now, my one more site is down for last two days in Google by targeted keywords. What should I do for that, now?
May site owners that have one hosting account will crosslink their sites. Google has made it very clear that this is not to be done. It is called "SubNet Crosslinking". One of your sites will receive a PR1 and the others will recieve a "Gray Bar". Remove the cross links and wait for 6 months for the penalty to expire.
you need to do what linkassitant said and contact google. Do you have an account set up with google webmaster central? if so it can give you some ideas of any problems if you are being penalized.
subnet crosslinking is really bad and u should prevent that for your site.. to get ranking back participate in forum
Goole says your site will not be penalized for "hosting your site on a shared IP address" (quote from John during Google's "Tricks & Treats" webinar last month). Is that what you're saying about your sites being on the same IP? If so, you're not being penalized; not for that anyway. Check out the webinar info here: http://googlewebmastercentral.blogspot.com/2008/10/reflections-on-tricks-and-treats.html
Be careful not to overreact to temporary dips in rankings. Rankings always will drop. And then they go back up, many times higher than before. The only reason you would be penalized is if your two websites have duplicate content on them, or if you did something that looked like spam to google or se's such as over doing keywords in title or meta tags, etc. Give it time. Usually rankings will come back. Just work on quality link building each month and your overall rankings should increase.
That "having more sites on the same ip and inter-linking them" doesn't sound like the reason for your SERPS drop. What links have you built to your websites other than the ones from the other websites? Did you use different keywords when getting backlinks or was it the same keyword allover the place? Other than that the type of content you have (unique or not unique) and the on-site SEO (especially over doing it) seems to be the case this time.
Totally lost by this post. Keywords don't go down. Google doesn't give a &^*%$ about you site (or mine for that matter) unless you are feeding them cash! Think of all the pages they index. Do they have time to apply a manual penalty? NO! That is about as logical as you looking up at all the stars in the sky and thinking you could count them. Too many people BLAME Google when they can't find their sites. And it is nearly always some oversight on the part of the webmaster. Especially new webmasters. Google penalizes sites with SOFTWARE... and automatically based on some filter a site gets caught in. Join Google Webmaster, submit your site and figure out why are are not performing.