Many Web developers these days feel a sleep-depriving mix of unbridled enthusiasm and nagging concern over Facebook's social-networking platform.

Opened to external developers three months ago, the Facebook platform and tools are well designed and offer developers generous revenue opportunities rare among social networks, along with a fast-growing and deeply engaged community of people.

However, this paradise is already getting soiled by developers who, eager to spur the adoption of their applications, design them with self-promotion features that many say are deceitful and trigger annoying and abusive actions, such as bulk unsolicited e-mails and intrusive message displays.

Although Facebook has acknowledged the problems and in recent weeks outlined corrective measures, it's critical for the company to quickly tighten its rules and unleash stricter penalties, developers say.

"It's definitely a problem that needs to be solved. There are additional steps Facebook could and should take," said Ali Partovi, CEO of iLike, which rebuilt its music-discovery site within Facebook in May.

As things stand now, the situation is a cat-and-mouse game, with developers seeking and exploiting loopholes in its terms of service and the company plugging them after the fact, he said.

By then, however, the damage is done, and the developer who exploited the loophole boosted adoption of his application, to the detriment of competitors who respect the terms' spirit, Partovi said.

That prompts honest developers to look for the next loophole as a defensive competitive measure. "That creates an unnecessarily bad environment," he said. "If the rules were simply enforced with clearer penalties, these companies would all fall into line quickly."

Partovi said his company has been watching this situation from the sidelines, because, in its category, iLike has a dominant position and feels little competitive pressure.

But he sympathizes with developers embroiled in competition with each other. "When you see your direct competitor exploiting a loophole and growing very rapidly and beating you, it's hard to resist the temptation," he said. "To some extent the blame is on Facebook."

This comes from someone who otherwise couldn't be happier with the Facebook platform and with the effect it has had on his company. In just three months, the iLike Facebook application has close to 7 million users, almost twice as many as on the company's own Web site, leading to a doubling of the company's revenue, Partovi said.

Unlike other social-networking sites, which limit the revenue-generating capabilities of external applications, Facebook has a policy widely considered generous, letting development companies run ads and engage in other commercial activities.

This has contributed greatly to the attractiveness of the platform for developers. At press time, Facebook's directory showed more than 3,500 applications built for the site by outside developers.

"The monetization is one of the most unique things they are doing," said Tim O'Shaughnessy, a co-founder and partner at Hungry Machine, which has developed about 15 Facebook applications. "That's what's causing the fervor over the application development. People are looking at the potential to enhance their business. It's not just a distribution play. It can put real dollars in your pocket."

Joseph Aigboboh, co-founder of J-Squared Media, another Facebook developer, agreed. "Facebook has created an opportunity to build literally any product and spread it virally to achieve unprecedented rates of growth and retention. This means that with a relatively cheap budget, companies can build lucrative products and services [and] drive revenue," he wrote in an e-mail.