joining us now we have scott kessler from i.t. group, director of i.t. t s&p iq and then we've got a senior analyst from r.w. baird. scott, let me start with you, you have a sell rating and a target of $43. you think twitter has 15% more downside from here. why so pessimistic? >> right. well, simon, i mean, truth be told, we've been, let's say, in the sell camp for a few months at this point. and one of our primary concerns has been related to user engagement growth. we pointed out, for example, that in q-3 twitter actually saw timeline views per user as flat from the prior quarter and they dropped 10% in the fourth quarter. we think that's a worry if they make big changes we're not so sure how that's going to affect other elements of their platform. >> but, scott, isn't the reason that the timeline views this dynamic that they use is down is because they are better connecting the conversations so people don't have to refresh and the photos and the videos are directly available within those timelines? i mean, if you look at the average revenue per user, i