On 8/19/07, Rob Church <robchur(a)gmail.com> wrote:
* rel="nofollow" *does not mean* "do
not follow this link" - this is a
known issue with the naming of the attribute value
* User agents are free to ignore it
The question is, do Google, Yahoo!, and/or Microsoft follow
rel="nofollow" links? Those are the three major spiders in my
experience, and stopping them from wasting their time would certainly
save a lot of page views.
I wouldn't underestimate the effect that can have on a server, either.
At times on my site, the majority of users are spiders. Randomly
checking now, I find my bulletin board's session tracker registers 89
bots active in the last 15 minutes, out of 537 users. I've
occasionally had several hundred bots active -- the record my board
keeps for "most users ever online", 1242, was mainly bots. Not that
those figures are scientific (they record logged-in users plus IP
addresses with at least one activity in the past 15 minutes, not total
number of activities in the past 15 minutes), but I have no doubt that
it could make a significant performance difference to be rid of
unwanted bots, and result in faster indexing because they don't have
to toss out the contents of the pages they request.