Can you point to anything that indicates a consistent trend towards "big tech companies", especially ones that stay successful for a long time?  Relational databases are the only one I can think of at the moment (Oracle, DB2 and SQL Server being the Big-3 here).  And note how people are using non-SQL databases to get a lot of things done that were once the domain of relational databases.<p>(In the data warehouse/OLAP field, don't there continue to be a lot of small and medium players?)<p>One thing I noted about Microsoft before the Ballmer era was that the secret of Microsoft's success was consistently writing software that basically works.  Microsoft in large part "won" by default, too many of its competitors lost that ability (and many would say Microsoft started losing it with Longhorn).<p>Let me explore this a bit more: I say that there's something fundamentally different between the middle two companies/areas you cite and Oracle's with databases.  Oracle has a <i>large</i> core of code <i>it</i> has to keep working.  If Sun went poof, the Java ecosystem would continue without much pause.  If/when Yahoo goes poof, will anyone significantly outside of it <i>really</i> care?<p>(I don't know enough about PhotoShop to comment on it, and while it's non-trivial to become a big search engine, enough companies continue to try at something like Google's scale (e.g. Yahoo, Microsoft ... and look at Wowd for a disruptive attack on the problem) that I'm not too worried as of yet.  Ah: PhotoShop is a sticky application, switching to another vendor is expensive, search is not.  Advertising is in between.)<p>I think it's more than new markets.  E.g. Java was aimed at one new market (appliances), released for another (web browsers), but ended up being wildly successful in the second oldest (data processing; only number crunching is older ... and Sun is addressing that with Fortress in the Java ecosystem).<p>Search was not a new market when Google appeared on the scene, e.g. it replaced AltaVista for me.  This is a field where creative destruction can renew a sector instead of just replacing it.