[gojomo]

Use of true clock time in these formulas penalizes posts that are submitted at low-traffic times.

Using a virtual clock, such as a tick count based on traffic (number of other submissions, votes, pageviews, etc.), could adjust for this.

[brent]

Good observation. I believe a similar concept is used in high frequency trading (in markets such as foreign exchange). So derivatives are not dt, but du where u is a surrogate for time in ticks.

[bluelu]

that's an interesting idea!