Following the launch of its web-based software applications such as Google Spreadsheets and Google Calendar, Google Inc. is set to strengthen its grip on the web-based software market with the acquisition of JotSpot.

JotSpot, which was founded in 2004 by entrepreneurs Joe Kraus and Graham Spencer, was the first company to offer wiki applications, where approved users can edit and update documents without knowledge of HTML. 

JotSpot's software, which is increasingly seen to be an online rival to Microsoft Office, currently has 30,000 paying customers and about 300,000 free users. Under Google, the service will be free and Jotspot will be incorporated into other Google services. 

Earlier in the year, Google purchased online word processing service Writely, which has now been repackaged along with an online spreadsheet application as Google Docs. 

The terms of the deal have not been disclosed.