It can go either way, depending on whether the algorithm favours the results or not. Its very usual to see an immediate decline, could only be 24 - 48 hrs, then increase, whilst the algorithm calculates whether to favour or negate the change based on its computation.
Long term results are difficult to measure, as they are always a guess. Testing and adjusting is everything with rankings. Testing usually must be done over 3 month periods to get an accurate assessment, some changes you only need a week or two to see improvement or decline. From a community where content is growing daily, then you should see a steady increase in traffic annually. For a static site, ie. business, things are much different and you really need to either make the site interactive with blogging, support, etc, or build advertising across the niche market.