There is cumulative evidence suggesting that hyper-glossing facilitates lower-level processing and enhances reading comprehension. There are plentiful studies on electronic dictionaries for English. However, research on e-dictionaries for languages with no boundaries between words is still scarce. The main aim for the current study is to investigate the usage and efficacy of e-dictionaries for Japanese language learners. This article reports the results of two studies concerning e-dictionaries: a survey study investigating the use of e-dictionaries (with a particular focus on e-glossaries that change a digital text into a hypertext) by L2 learners of Japanese, and a comparative study examining existing e-glossaries to evaluate whether they provide the optimal level of support for reading Japanese e-texts. The results of the survey showed that learners have their preferred e-dictionaries (in most cases, "e-word dictionaries" in which the user can look up individual words), and that few learners are aware of the existence of e-glossaries. The results of further study revealed that existing e-glossaries have various functions, but lack some requisite information crucial to the target language. This study suggests that technical issues revolving around the lack of spaces between words may be a reason for the lag in usage and efficacy of e-glossaries for languages without word boundaries.