BT complained about the wording of the claims, which were made in an email and a piece of direct mail.
BT argued that the phrase 'AOL Talk gives you so much more than BT' exaggerated the benefits of AOL's service over BT's.
The telco also believed that the statement 'So if you resent paying over the odds for your phone calls, change to AOL Talk' was misleading because it implied that all calls would be cheaper with AOL Talk than with BT.
The ASA found against AOL in both instances, citing breaches of the CAP Code in the areas of substantiation, truthfulness and fair comparison.
"The ASA considered that recipients were likely to infer from the claim 'AOL gives you so much more than BT' that AOL's service was superior to BT's in all respects," said the ASA ruling.
"Because AOL had not proved this, we considered that the basis of the comparison was not clear or fair and the claim exaggerated the benefits of AOL's service over BT's."
On the second point, the ASA found that AOL had not listed all of the benefits of BT's Together CallMobile package, which would make calls to mobiles cheaper using BT's service.
"We considered that, in the context of the ad, recipients were likely to infer from the claim 'So if you resent paying over the odds for your phone calls, change to AOL Talk' that all phone calls made with AOL's service were cheaper than with BT's," the ruling said.
"In the absence of reference to discounts that were available with the BT Together packages, the ads were likely to mislead on that point."
The ASA told AOL to remove the claim that 'AOL Talk gives you so much more than BT' and to avoid the implication that all its calls were cheaper than BT's.
AOL was also advised to consult the CAP Copy Advice team before running any similar ads in the future.
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