I am currently working on a web site based in the UK and have identified a number of legacy issues that may have been having a negative effect on the site’s rankings. The site has been suffering from significant, frequent ranking fluctuations in the Google SERPs over the last 12 months and fluctuations have started to reduce in the last month or so. I’ve been informed by the website that it may even have been penalised in Google at one point a few years back. The website also had a URL re-writes that were not re-direted properly which caused rankings to drop significantly in October 2008. The company has sub-domains that have since been abandoned and many timed out or returned 404 errors. There were potentially thousands of these subdomains, many of which had links to them. Rather than having hundreds of thousands of pages on the domain return 404 errors, we 301 redirected the ‘dead’ pages to the homepage. Tidying this sort of thing and many other legacy issues up has certainly had a positive impact – ranking fluctuations are less extreme but are still significant (jumping 20-100 places at a time rather than 100-500). One of my main queries though is whether redirecting old subdomains that have no relevance to the site being redirected to (as is the case here) is best practice. For example we have an old sub domain which has many links with the one specific anchor text. Having redirected this subdomain to the home page it now ranks page 1 in Google UK for this specific term. The domain is obviously not at all relevant to that keyword and the ranking is there just because of the links pointing to the redirected subdomain. One worry I have is that the irrelevancy of such links could dilute the ‘theme’ of website we are trying to optimise and therefore have a negative impact on rankings? With potentially thousands of these subdomains, all with links pointing to them, there is a good chance that some links are from bad neighbourhoods. If this could be impacting rankings is there another implementation you recommend? Other issues that we believe may have lead to ranking fluctuations we've experienced are: • Old hidden banner links at URLs. There are many of these that we cannot change and are out of our control to change. • We have made implemented 301 redirects from URLs that were previously 404 errors. However as we were concerned that some links to the original URLs may be from bad neighbourhoods we have excluded them via robots.txt. I’d be grateful if anyone could provide some advice on what is best practice in this situation. Do you feel I should formally enter a reconsideration request via Google Webmaster Tools citing all the issues we have?