While scientists since Fritz Zwicky and Vera Rubin have looked for "dark matter," Mordecai and colleagues have been developing MOND as an alternative for the last 25 years. Since DM has never been directly observed, the field is open to alternatives. He claims that MOND can match the predictions of DM. The theory is far from complete, Milgrom admits, but today he was able to present before an international audience.
Though they sound similiar, "dark matter" and "dark energy" would be quite different if they both existed. One would attract and the other repel. They possibly share the quality of being misnamed. DM could be made of Black Holes that have never been matter at all. DE can be explained by a changing speed of light. They are both inferences that have never been directly observed.
One of Mordecai's slides had an interesting equation:
a ~ cHo
This is remarkably similar to R = ct, suggesting that they are on to something. (Thanks to nige for pointing out the correct form, which he has pointed out before.) It is good that alternative ideas are being heard.