The BT technology, called Cleanfeed, has been introduced by BT Retail to prevent any of its Web users accessing sites that the Internet Watch Foundation says contain paedophilic images.
Cleanfeed was introduced by BT on 21 June. The telco revealed on Tuesday that by 13 July, 230,000 requests to access the blacklisted sites had been refused.
BT says that Cleanfeed is a 'step in the right direction' in the fight against Internet paedophilia. It has also pointed out that rival ISPs are welcome to use Cleanfeed, and says it is in discussions with several operators about sharing it.
But despite the positive publicity BT has won for its move -- with more than 50 MPs giving their backing -- it appears that the issue isn't as clear-cut as it might appear.
AOL says it is talking to BT about Cleanfeed, but claims that there are several problems that need to be overcome.
"The goals they are trying to achieve are very commendable, and they are goals we share. But it's not clear that all the issues we care about are being addressed," said Jonathan Lambeth, AOL UK's director of communications.
According to Lambeth, it's relatively easy for BT Retail to offer this service because it only uses BT's own network for its Internet services. Other ISPs who resell services from a range of telcos wouldn't be able to offer Cleanfeed unless all their suppliers had embraced it.
There is also the possibility of legal action if a legitimate site was added to the blacklist by mistake, he said.
"If all ISPs blocked that site and it suffered a huge dip in traffic, they potentially could sue for lack of business," Lambeth suggested.
There have even been suggestions in some parts of the UK Internet sector that BT has been making too much of Cleanfeed's results, with BT Retail chief executive Pierre Danon appearing on a number of media outlets on Tuesday morning.
"It needs to be about more than just PR," said Lambeth, who pointed out that many child-pornography rings used other technologies than just Web sites, such as email, FTP and peer-to-peer.
"Cleanfeed is just one part of the solution to just one part of the problem."
Talkback
one of the other questions is is it possible to spoof ip addresses and cause the blocking of innocent sites.
I think that a worm could spread an auto dialler to dial onto compromised computers, to dial some of these sites, in order to get onto web crawlers, and this is probably increasing BT figures.