For some people the 15th of the month is just another day (tax deadlines in April notwithstanding), but for garden-lovers across the blogosphere, its a monthly holiday: Garden Bloggers Bloom Day.
It's an online event, started by garden blogger Carol at May Dreams Gardens, where green thumbs are encouraged to blog about what's blooming in their gardens that month.
I'm sure that doesn't sound like much: Garden bloggers are obviously going to blog about their gardens, right?
That's true, but the reason I bring it up is that the event has seen its popularity explode over the past couple years, with more and more top gardeners and garden photographers getting involved.
And all of these bloggers writing about one topic is not only building buzz about gardening, but strengthening what was once a smaller niche market in the blogging world.
Although Garden Bloggers Bloom Day isn't meant to promote any product or service in particular, gardening as a whole is becoming a big topic of conversation in these blogs, and that fact alone is what makes massive blogging collaboration like this so important.