Let's say someone had previously marked a site or part of a site off-limits by robots.txt and Google recognizes and obeys that indication. Later the webmaster decides he does want Google to crawl those portions of the site again and removes said restrictions from the robots.txt file. How long till Google will come through and crawl those pages? Does Google have a default time period that it will set to come check the robots.txt again? I have one site where robots.txt made the whole site off limits to search engines. I removed this quite a while back, but Googlebot hasn't been back to crawl the site since March 15th, according to Google Webmaster Tools. Help! I would like to have Googlebot over for a visit so it could crawl the site... (And yes, I have uploaded a nice sitemap in Webmaster Tools as well. Still nothing in the site is indexed, and Googlebot hasn't returned to index things).
google checks the robots.txt file before crawling your site. because of this, if you allow google to crawl your site, it will effect on the next crawl
yeah but that's what I'm saying - the last time Google appears to have accessed my site (March 15th), it was told to not access my site. The question is, how much time passes before Googlebot comes through again to see if it is welcome?
It should be immediate. Create a nice sitemap and submit to google and please add fresh content to your site and continue link building. Check the codes carefully for any other restrictions.
I would try and funnel the googlebot to these areas of the site. put a link on your homepage to the section of the site and get more deep links...