It is my opinion that as more companies out side of America enter the market, the higher the risk is for US tech companies. Although it is wishful to think that Americans would stay with US-based companies, many people would rather go for the newest, biggest item at the lowest cost.
Even so, cost isn't as important if different companies have more to offer. As a US tech company, I would be concerned about the competition and momentum Alibaba is bringing to an already saturated market of consumers.
Alibaba shares opening at $68 is a sign that investors are expecting Alibaba to give companies like Google and Microsoft some stiff competition. And for good reason. Alibaba is the preferred search engine for most of the Asian market and their introduction into the American market will give them an ever increasing presence in the global market as a whole.
The rumblings are that Alibaba is going to be taking aim at the biggest US conglomerates in the tech field. Both Amazon and Google are expanding their reach beyond what they started out as, so why wouldn't a company like Alibaba plan on doing the same? No one really knows what Alibaba will do, especially with the possible weight of the Chinese government behind it.
US tech companies do not need to be worried about Alibaba. I believe most of this is hype and will all die down in a couple of weeks. I do not believe they are a good company and most people will realize this eventually and their business will slow down.