Writing text for the web should be approached in broadly the same way as for a normal piece of marketing, but with intent.

Collateral has been produced for a hundred years with the customer in mind. The web is now different save for one crucial factor. This is that there are normally two customers to satisfy with writing on the web, one is the customer you must reach, and the other is the algorithm you must impress to rank in Google so as to be found by that target customer.  

Although it is very smart, the Google algorithm is a computer programme and as such it cannot be expected to be sophisticated when interpreting a message. Hence preparation work is highly desirable.  This work would consider several factors such as :

• What are the key phrases (or strings) associated with the product
• Of these strings which ones can the page be optimised for 
• How many times are those particular strings searched for on Google, and what are the chances that people typing those words into a search engine will also be the people who can buy, or influence the buying of a product.