I know very little about typography. What are the differences in terms of OpenType vs. TrueType?
I do know that they are types of formats to render fonts (correct me if I'm wrong).
Are there limitations between OpenType and TrueType?
They are file formats for storing font information.
TrueType was invented by Apple as a competition to Adobe's PostScript Type1. Both TrueType and PostScript fonts became the standard file formats for fonts for the past 3 decades or so of desktop publishing. In terms of your average designer, the differences between the two are relatively unimportant.
OpenType was designed to replace these and was created initially by Adobe and Microsoft. It's basically a newer format that is more robust. For a designer, the primary benefits of OpenType over previous formats are a) an much larger character set and b) automatic alternative character and ligature support (for software that supports it).
Wikipedia covers it well:
Adobe offers some great reading on type formats: See Adobe explanations here
Excerpts from the link:
WHAT IS TRUETYPE?
TrueType is a standard for digital type fonts that was developed by Apple Computer, and subsequently licensed to Microsoft Corporation. Each company has made independent extensions to TrueType, which is used in both Windows and Macintosh operating systems. Like Type 1, the TrueType format is available for development of new fonts.
WHAT IS OPENTYPE?
OpenType is a new standard for digital type fonts, developed jointly by Adobe and Microsoft. OpenType supersedes Microsoft's TrueType Open extensions to the TrueType format. OpenType fonts can contain either PostScript or TrueType outlines in a common wrapper. An OpenType font is a single file, which can be used on both Macintosh and Windows platforms without conversion. OpenType fonts have many advantages over previous font formats because they contain more glyphs, support more languages (OpenType uses the Unicode standard for character encoding,) and support rich typographic features such as small caps, old style figures, and ligatures — all in a single font.
Beginning with Adobe InDesign® and Adobe Photoshop® 6.0, applications have begun to support OpenType layout features. OpenType layout allows you to access features such as old style figures or true small caps by simply applying formatting to text. In most applications that do not actively support such features, OpenType fonts work just like other fonts, although the OpenType layout features are not accessible.
OpenType with PostScript outlines is supported by the latest versions of Adobe Type Manager, and is natively supported in Windows 2000. Apple has also announced its intent to support OpenType, and supplies Japanese system fonts for Mac OS X in OpenType form with PostScript outlines.
The above link to Adobe, though helpful, is a bit outdated (makes references to Photoshop 6, for example).
Here is the updated link for the Font Formats (True Type, etc):
In simple words , Truetype are those fonts whose style cannot be edited or changed according to will. That is , suppose you want to make a later a bit streched or make a fine change in it , you can't do that in Truetype fonts. But on the other hand, in case of Opentype fonts you can do such changes. Opentype fonts' style are editable.