AOL Time Warner’s share price fell to its lowest level for almost a month on Thursday after a leading internet analyst cast doubt on the advertising outlook at its America Online unit.

The revised forecast came from Lehman Brothers’ Holly Becker, who wrote in a research note issued Thursday that much of the online division’s advertising came from other AOL TW units, while a number of ad deals with external clients will shortly expire.

On this basis, Becker slashed her estimate of America Online’s first-quarter ad revenue by 17% to $535 million (€609m; £375), dragging down the unit’s total revenue from $2.45 billion to $2.35bn and its EBITDA (earnings before interest, tax, depreciation and amortization) from $501m to $449m.

Such declines would, says Becker, push AOL TW’s overall Q1 revenues down by 3% to $9.4bn, with EBITDA sliding from $2.1bn to $2bn.

Becker’s forecasts, however, were not America Online’s only concern. In a humiliating U-turn, AOL TW has abandoned the edict that all its divisions use an email system based on AOL products.

After nearly a year of trying to implement the scheme, AOL TW finally listened to the Niagara of complaints from every level within its corporate pecking-order that the inhouse system was unsuited to business use. On Wednesday it announced that all divisions could use whichever email software suited them best – including products from rivals IBM and Microsoft.

Gripes against the system included frequent crashing, the inability to email large attachments, users being booted offline without warning and the automatic labelling as spam of multiple internal emails sent to large groups of staff.

Data sourced from: The Wall Street Journal Online; (USA); New York Times; additional content by WARC staff