Is it possible for certain pages to be hit by a -150?

[herculano]

July 29th was the day when a lot of our pages got hit and one of our very good money page seems to be hit by a -150, but one of our main keywords still show up on the first page of G.

A couple of observation:
1. our domain is exactly 6 months old on 29th of july.
2. links to our main page is about 2000 and the page mentioned above has about 1000 according to G's WMT, those are approximate numbers and other pages of the site has different ranges since we don't control the links coming to our site.
3. we've seen an increase in google.com/?url= redirects in our tracking not sure if it's because of any redirect hijacking.
4. our main page is still on the first page G but not no. 3,4 or 5, but mostly around 8 or 9.
5. the page above use to be around 4 or 5 now it's at 150+.
6. we tracked about 40-50 keywords to be around the first page of google in the span of about 2 months, most are gone, some are still page 2 but most are gone, meaning.. 300+, 400+ positions.

Anyone seen this behavior before? I'm not really sure if there's a possibility of hijacking, I hope not. Any help is appreciated!

best regards.

[tedster]

There are all kinds of new and previously uncommon changes showing up in the past few weeks, although the most common is minus five pages and not fifteen. For more, see our discussion in the thread: Google Updates and SERP Changes - August 2009 [webmasterworld.com]. -150 sounds like a variant on what we used to call the minus 950 penalty [webmasterworld.com].

I'd suggest a close study of the rankings at different times of the day - and perhaps keeping a record of the responding IP address (data center) at Google go gather information.

A note - it may be the url itself that is having struggles, or perhaps that url but only for this particular query. Penalties can be applied just for one search term, or to the url in all situations.

[herculano]

A note - it may be the url itself that is having struggles, or perhaps that url but only for this particular query. Penalties can be applied just for one search term, or to the url in all situations.

tedster, thanks for your reply, you are right we are observing this... it's the same url that use to rank pretty high in several keywords some remained high.. in the first page of G other keywords drop to 300+ then today it was back to 27 but not the first page yet, it looks like G has been doing some sort of dance again... for relatively newer sites...