Asana, the fast-growing work-tracking tool created by a co-founder of Facebook, today declared war on Trello, its biggest rival. Asana, which has to date been known for its collaborative to-do lists, today introduced boards — essentially a note-for-note re-creation of Trello’s rival approach to getting things done. The move could accelerate the growth of a once-arcane sector of the software world into a default tool used across a broad range of industries.

Until now, the divide between lists and boards has essentially been religious. Some believe the most efficient way to work is to create lists of tasks and assign them; others believe it’s more efficient to visualize those tasks on cards and arrange the cards on a digital whiteboard. People particularly like boards for tracking the state of objects — moving a job candidate through the recruiting pipeline, say, or moving an article from conception to publication.

This summer Asana introduced what it calls “custom fields,” which among other things let users track the state of various projects by adding in their own dropdown menus and text boxes. I’ve found them tremendously useful myself — but still, everywhere that Asana goes, people are always asking it to build boards. Specifically, to build Trello boards. And they refused to switch from Trello to Asana unless Asana had boards.

So, Asana built boards. “We want to give Trello full credit here,” said Justin Rosenstein, an Asana co-founder, in an interview. “They’ve done a great job popularizing this easy visual view. But we see a much bigger opportunity here to enable more kinds of work.” In Asana’s opinion, a board is just one way to view your work — and until it’s connected to a more robust system for tracking work, it’s not half as powerful as it should be.

In the first version of boards, you have to build them by hand. It’s easy — you create labels for some columns, add “cards” by typing in their names, and move them around however you like using drag and drop. What’s more interesting is what’s coming next. Within months, Rosenstein says, “boards” will simply become one view inside Asana. If you like using lists to get your work done, you can stick with lists. If you prefer boards, you can tap “boards” and visualize your list of projects that way. Different colleagues can work according to their own preferences. And different projects can take the shape that best suits them.

Boards are flexible tools for visualizing work, Rosenstein says, but ultimately underpowered. “This is a great feature, but it’s not a product,” he said. “It deserves to be a product instead of a feature.”

“This is a great feature, but it’s not a product.”

I’m deeply interested in workplace productivity — I’m the sort of person who downloads a dozen to-do list apps just to assess the minor differences in their user interfaces. There are some amazing single-player tools available — Todoist in particular has been a joy for me to use.

But ultimately to-do lists are most powerful when they’re connected to everyone you work with. Investors seem to be waking up, if slowly, to this fact. This year Asana raised $50 million at a $600 million valuation. Trello says it was already profitable when it spun out of Fog Creek Software in 2014 with $10 million in venture funding.

Both products use a freemium model, but the free version of Trello is much more robust — one reason it grew to 10 million users as of last year. Asana says that around 13,000 businesses pay to use it; Trello doesn’t disclose its number of paid users. (There are other competitors in work tracking, too: notably Basecamp, which arguably invented modern web-based collaboration software, and JIRA, the preferred choice of many software companies.)

By integrating lists and boards into a single product, Asana may have just vaulted ahead of its rivals. Its version of boards doesn’t do everything that Trello’s does out of the gate. But in bringing together list people and board people, it just gave Trello an enormous reason to worry.