Historically small business has had no chance of competing with large corporations in the marketing area.
The costs of using traditional advertising channels, such as TV and print were high and small businesses couldn't afford to employ the marketing people to do the non-advertising marketing such as PR and promotion.
The emergence of the web in the 90's provided small business the opportunity to get global reach but again the cost of technology solutions and lack of IT people meant that many small businesses established websites that cost a great deal and had little impact.
From the earlier part of this decade things have really changed. Small businesses can now access best of breed software tools and even methods on how to leverage the Web. A change indeed!