I suppose this varies, depending on the companies involved, the size of the acquisition, and the reasons for doing the deal. If it is a talent acquisition, I w

I suppose this varies, depending on the companies involved, the size of the acquisition, and the reasons for doing the deal. If it is a talent acquisition, I would imagine the goal would be for you to stick around as long as possible (say, years?). If it is a technology acquisition, they likely only want your tech, code, or patents, and wouldn't mind if you just stuck around for the transition (say, months?). When I worked at Internet Brands (née carsdirect.com), we would see maybe 20 acquisitions per year. These would be income-generating websites acquired for an average of $1 million each. Generally, IB only wanted the site, the community, and the impressions. They would usually keep the founder, a lead dev, and a webmaster from the original company around for 6 months to a year while the site was transferred in-house. We would rewrite the code in PHP whenever possible, move the site onto our standard LAMP stack, hosted on our servers, and migrate any blog to WordPress, static sites to MovableType, and forums to vBulletin. Then the founder would stay on as the public face of the site with up to a 3 year earnout based on maintaining similar or increasing levels of traffic and revenue. After that, they usually disappear as soon as the last earnout check clears.