i agree that there is a huge percentage of an individuals post count is irrelevant in terms of content and unfortunately something every forum active member is guilty of, that being said it is a necessity in greeting new members and promoting how active our forums are so in effect is a useful tool
Thankfully, advertisers and sponsors do not check for content in their consideration processes and tend to only focus on the total activity.
its small and pointless activity which leads to more quality posts/ threads. think of the greeting posts as kindling to a fire