The most important email clients support the display of animated GIFs. Only exception is Outlook 2007. This constraint should not be a problem, just keep in mind that only the first frame of the GIF is displayed. This should therefore be carefully selected.
Examples of animation in newsletters and email campaigns:
MarketingSherpa published a study of the chocolate supplier Lake Champlain Chocolates. They produced stunning results after the use of animated GIFs. With very great effort, two different product animations were developed and integrated into an attractive email layout. After extensive testing the actual shipping was achieved with a well acceptable deliverability – after all the email had a file size of several hundred kilobytes. The results speak for themselves. According to the corresponding Case Study on MarketingSherpa the click rate increased by 203% and the conversion rate by 49%.
That is of course very impressive and so imitators aren’t far behind. But one should remember that this effect might wear off due to excessive repetition. Lake Champlain uses the animation therefore only on special seasonal events. Also the target group, the advertised product, the other contents of the email, and especially the animation itself must be consistent and maybe the file size can be reduced.