There's long been a problem of spammy bumping being used to keep topics near the top, but lately it's become unbearable. Therefore, on these boards, bumping has changed:
 - Service Announcements
 - Announcements (Altcoins)
 - Tokens (Altcoins)
 - Bounties (Altcoins)

Topics are no longer ordered by last post on these boards. Instead, each topic has a bump score which is calculated based on recent "bump events". Posting in the topic once per 7 days increases the topic's bump score. Clicking the new "bump" link (near "watch", "print", etc.) once per day increases the topic's bump score up to 100x as much, but it also decreases the power of your future bump-link-clicks for 30 days. Neither action is guaranteed to bring the topic to the top, since it only increases the topic's score.

I can see several things about this which may not be ideal, so adjustments will likely need to be made, but something is probably better than nothing.

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What you need to know

 1. Don't worry about it too much. If you behave as normal, you'll do OK.
 2. If you like a topic and you see a "bump" link near the "watch", "print", etc. links in a topic, click it.
 3. If you've been spam-bumping, knock it off, since it's not going to work anymore.

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Technical details

Base bump power

Your base bump power is the smaller of these two values:
 - The activity you would have if you'd signed up 1 year ago.
 - The merit you've earned in the last year.

If it's zero (as it will be for newbies), then you don't bump at all.

Mini bumps

If you haven't posted in a topic in the last 7 days, posting in it adds 1% of your base bump power to the topic's bump score. Deleted posts count against the 7-day limit, but not the topic's bump score.

Super bumps

Once per 24 hours, you can click a topic's bump link. When you do this, a modified bump power is calculated as something like your base bump power minus 15% for every super bump you've done in the last 30 days, and this is added to the topic's bump score.

The exact contribution is b*(1-0.15*^s/_b), where b is your base power and s is the total you've contributed to bump scores via super bumps over the last 30 days.

Bump score

A topic's bump score is affected by the above two actions over the last 36 hours. Each action's effect decays linearly over the 36 hours, so an event which contributed 1 at the beginning will contribute 0.5 after 18 hours.

Topics with equal bump score (such as topics which haven't been posted in for 36 hours) are sorted by last post time.

Non-default sorting

On the targeted boards, sorting under this scheme is the default. You can go back to the older sorting by clicking the "last post" column header twice.

On the non-targeted boards, you can see the sorting under this scheme by using a link like https://bitcointalk.org/index.php?board=1.0;sort=bump;desc . I'm not sure if this is at all useful. (It's also possible to super-bump topics on these boards, though there's no real incentive to do so.)

Non-publicity of data

For now, I am intentionally not making it public who bumped each topic, since that way you can't prove that you bumped anything, and this may prevent people from selling their bumps as easily. I don't particularly object to making the approximate bump scores or bump powers public, but I didn't do this yet.

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If you find bugs, PM me.