Online poker firm PartyGaming said revenue since 6 April has been in line with that achieved in the first quarter, though full-year distribution costs are expected to be slightly higher than forecast.The group said it has increased marketing spend in certain territories in an effort to capitalise upon the recent seizures of player funds from US-facing sites by the United States Attorney's Office of the Southern District of New York. This is expected to lead to distribution costs being slightly higher than the previous full year guidance of 38-40% of net revenue. However, continued cost savings and favourable currency movements have meant that lower staff and overhead costs have offset the increase in marketing costs and consequently, Clean EBITDA margins for both half year and the full year results are still expected to be in line with that achieved for the full year in 2008. Casino revenue has shown a 'significant' increase from the first quarter despite a fall in casino active player days due to seasonality and lower levels of cross-sell from poker. As expected, poker has seen a marginal reduction in active player days versus the first quarter due to seasonality and continued strong competition from US-facing sites. However, an enhanced player loyalty programme, improved player promotions and a new offline marketing campaign saw each of these metrics improve last month. As a result of these initiatives, poker yields have been softer than in the first quarter due to increased bonus and player loyalty costs, resulting in a reduction in poker revenue versus the first quarter.Sports betting revenue was down on the previous quarter reflecting a reduction in betting volume due to the end of the season for European football, that remains the single most popular sport for betting customers."PartyCasino, the world's largest online casino, continues to go from strength to strength, with strong double digit growth quarter-on-quarter despite difficult economic conditions. We look forward to the rest of the year with confidence," said chief executive Jim Ryan.