my site got good ranking and stable for a long time and in past 2 days i make nofollow on my homepage to flow pr to inerpage i want. then today, i change the title of homepage & reduce the length of title and trim title of hundred of innerpage. I found, rank down for keyword emphasized. rank up for keyword existed before. rank up down for keyword deleted from title(should be) is it dangous to trim title of hundred of innerpage( most of my innerpage)
Google is wary of any mass changes. It is normal to temporarily lose rankings when you make drastic on-page changes. Usually you get those rankings back after a little while. It may help to build more quality backlinks and submit a new sitemap to Google.
When I changed the title of my blog, my search engine positions dropped a bit too. What are the keywords for the anchor text links pointing to your site?
Good advice... If you are fairly confident that the changes you made should help you then as vansterdam stated, I would just ride it out a bit. When you make changes like this it takes Google days, sometimes a few weeks to 'absorb' the changes. Typically your rankings will come back assuming link text of your inbound links and the on-page <h1>, <h2>s, and content of the page now match better. If your <title> used to say "Car Maintenance" and the majority of your inbound links have "car maintenance" as the link text and you rank well for "car maintenance"... and suddenly you change the <title> to "Auto Maintenance" but very few of your inbound links are using "auto maintenance" as the link text then your rankings will likely NOT recover. You will likely have hurt yourself by changing the <title> Though Google is smart enough to know that "car maintenance" and "auto maintenance" are VERY closely related, having inbound links with "car maintenance" as the link text will not help you as much to rank for "auto maintenance" as having inbound links with "auto maintenance" would help. Inbound links with link texts that exactly match your targeted phrase will help you more than those with link text that only partially match or which are related but do not contain the targeted keyword phrase. It is a good idea to vary your link text slightly for some of your inbound links. It looks more natural. But it helps to have most of the inbound links exactly match your targeted keyword phrase(s).
I agree with the above, after title changes I always see a downturn in traffic and then it usually comes back...the one time it didn't was when it coincided with a hack and I got a penalty.
Although changing the title can significantly affect your ranking, I find it a little strange that the change occured on the same day as you altered your title. Usually takes a few days to reflect this. Look to see when last your webpages were cached. it may throw some light on the issue