This has bugged me for awhile now when the jump in back links first happened I was overjoyed, most people were I guess :
But google didn’t show me what had doubled or why it had increased so much:
With a total link count of 134,741 to my blog homepage I felt kinda warm and fuzzy inside, but only letting me download 840 left me feeling cold and empty. so when we did soft launch on a re-branded site something jumped out at me, the new website was added to Google Webmaster tools mainly for error checking and crawl statistics I checked the IBL count it was zero after a few weeks we had pushed maybe 10 – 20 links into the site which where now showing in webmastertools , Happy that the site was performing the way it should be we 301ed the old url into the new domain.
I can still only download 20 back links form webmastertools but my link count is sitting at a sweet 639,640, so my guess is Google’s main IBL gap is your 301 back links which actually makes sense when I looked back at the www.davidnaylor.co.uk statistics I have 301ed the blog home page many times in the last few years.
BUT and this is a big but, recently I was looking at a website that had lost it’s rankings after many years sitting sweet in Google and I couldn’t really find anything wrong at first it looked like a link buying penalty but they hadn’t bought any links, the Google gap on the ranking pages showed me 4000 ibls that where not accounted for could this be a a competitor 301ing a bad site at the site, at present I’m still looking into what happened but it would have been a great help if Google said something like :
639,620 backlinks are from a 301 domain (to see these links added google362739624.txt to the old site)
20 are directly linking to homepage
at least I would have a heads up on a 301 attack and could have informed Google.