Weed-focused tech companies say they want to embrace digital advertising full throttle, but the industry is not quite ready for their business.

Display ad networks, social networks and search companies present varying policies regarding weed tech companies. Some digital heavyweights like Twitter and Google appear to be loosening up and allowing some ads from pot businesses. Others like Facebook appear stricter, according to weed tech entrepreneurs, and ad networks don't want to serve pot ads to mainstream websites or deliver ads from major brands to marijuana websites.

"There's a lack of support from tech companies in general for cannabis companies," said Paris Holley, co-founder of Mantis, an ad network for pot publications.

Holley said that much of the infrastructure set up to serve digital ads is unwelcoming to weed tech companies, so Mantis wants to fill the void.

Established players in digital advertising, like Rubicon Project and OpenX, are likely reluctant to serve ads to publishers that promote pot, Holley said. Also, brands are opposed to seeing their ads run on pot websites.

"There's just a fear that they'll put other companies in their portfolios at risk," he said.

Mantis has built a network of 60 pot websites to deliver ads from the companies sprouting around the legalized marijuana space.

The network might be prescient given that the weed tech sector—comprised of app producers, websites and other digital products and services—attracted $100 million in venture capital last year, and it is gaining legitimacy with more favorable marijuana laws around the country. Twenty-three states and the District of Columbia have legalized pot for recreational or medicinal use.

Companies like Cannabuild, which develops apps for pot smokers, say it's a shame all the digital marketing tools aren't widely available.

Cannabuild CEO Zach Marburger said he has actually set up campaigns on Facebook, and he would like to do more, but Facebook banned the ads. "We spent roughly $2,800 and then our Facebook ads were canceled," he said. "I wish I could have spent more; it performed so masterfully."

Cannabuild was able to target Facebook users who like the Showtime show Weeds and other interests. "It was fantastic," Marburger said.

Facebook does not allow ads promoting the use or sale of marijuana, according to its rules. It does allow certain ads that relate to advocating legalization.

But pot-focused tech companies that ran ads on Twitter and in Google search results found a slightly warmer welcome. For instance, MassRoots, a social network for pot lovers, has used Twitter to promote its app, according to CEO Isaac Dietrich.

"Google and Twitter are cannabis-friendly, right now," Marburger said.

Both of course have their limits. For instance, pot dispensaries advertise in search results, but the word "pot" and other direct references are not in the ads. Twitter blocks ads for pot-smoking products, but allows ads that promote news and information about pot, according to its rules.

Weed marketers are hoping the digital ad landscape becomes more navigable, and they don't have to resort to such careful wording in ad copy or fear having campaigns taken down.

"They can't leverage the tools to reach full audiences because of who they are and how they're marketing," Holley said. "These are the challenges running a tech business in the cannabis space."