I think you mean internal anchor text OOP.
Anyways, I had a site drop to 950 for 5 days or so, then it came back nothing changed.
Another site had a page drop, with all the other important rankings unchanged, then we removed it from the navigation menu and it came back almost overnight. Put it back in navigation and it dropped out almost overnight as well.
Third case scenario we created a new sub-domain. Mostly unrelated but for the demographic it makes sense. The 40 or so pages did great out of the box. 4 days later it went 950+. I'm not going to make any changes just yet, but will get 20-30 inbound links (low to medium quality) over the next 15 days to see how it goes.
Oh, and of note on that third case, it dropped about 1.5 days after we added a script that linked to one of the 40 pages from every 3rd blog post on the main domain. That was about 900 links or so. It used the same anchor text as the anchor text used on the sub-domain's navigation. Now, we've switched it to use each page's H1 as anchor text.
[edited by: tedster at 9:12 am (utc) on Feb. 8, 2007]