Generally, companies have targeted the gay and lesbian consumers for commercial reasons, based on a number of general assumptions – ‘supported’ by market research companies.
Also, political motivations played a role: a company wants to be ‘all-inclusive’, or show its tolerance by being present in the LGBT press or at relevant events.
In both cases, it seems safe to assume that general rules of marketing would remain valid, most importantly a targeted approach (based on market research), and constant monitoring of the results.
To find companies that would have something to say about this, I almost a thousand print publications and websites. When a company advertised (or sponsored) once or more often, I tracked their contact details and mailed them with a short introduction, and invitation to participate in my survey.
The survey took about 10 minutes to complete. More than 7,000 businesses were approached - a total of 1,191 entries were received, of which close to 1,100 could be used.